Discussion of ultramafic and mafic rocks and platinum-group element analyses from the Lost Basin mining district, northwestern Arizona

1986 ◽  
Author(s):  
N.J. Page ◽  
T.G. Theodore ◽  
L.A. Bradley
Keyword(s):  
Platinum Group Element ◽  
Group Element ◽  
Mining District ◽  
Mafic Rocks ◽  
Platinum Group

Stratigraphy, thickness, tectonic environment, and economic implications of the giant Suwar – Wadi Qutabah layered mafic complex in northwestern Yemen

2015 ◽  
Vol 52 (2) ◽  
pp. 134-146 ◽  
Author(s):  
Chantal M. Venturi ◽  
John D. Greenough ◽  
Chad Ulansky ◽  
Charles Fipke
Keyword(s):  
Platinum Group Element ◽  
Mineral Exploration ◽  
Group Element ◽  
Economic Implications ◽  
Mafic Rocks ◽  
Mafic Intrusions ◽  
Mafic Complex ◽  
East And West ◽  
Platinum Group ◽  
Layered Mafic Intrusions

The Wadi Qutabah layered mafic intrusion in northwestern Yemen, considered part of a giant (>250 km2), Neoproterozoic (∼638.5 Ma) intrusion referred to as the Suwar – Wadi Qutabah Complex, has significant potential for economic platinum-group element and Ni–Cu–Co mineralization. A search for platinum-group element mineralization at Wadi Qutabah yielded cores from 14 drillholes along two east and west lines. Stratigraphically, they reveal ∼500 m of interlayered norites with subordinate gabbros, anorthosites, pyroxenites, and massive sulphide layers showing modal and cryptic layering that can be correlated between individual holes and between the east and west areas. Energy dispersive spectrometry major element analyses on mineral phases show gradual upward changes in plagioclase composition from An52 (lowest level drilled) to An44, and En61 to En57 in orthopyroxene, up to a distinctive, ilmenite-rich unit termed 5a (augite norite). Above 5a, minerals show a dramatic shift to more primitive An57 and En69 compositions. The gradual changes are typical of layered mafic intrusions and reflect progressive crystallization of magma upward. The dramatic changes, such as above 5a, are also common and reflect magma chamber recharge. In addition to the 500 m reported here, mineral exploration data from more-mafic rocks at Suwar suggest 400 m of layered rocks below those at Wadi Qutabah (total 900 m). A regression analysis plot of the cumulus mineral (plagioclase and orthopyroxene) compositional change versus thickness for seven well-known, giant, layered mafic intrusions suggests that the Suwar – Wadi Qutabah Complex is >2 km thick and one of the largest (thickness and area) intrusions on Earth. Comparison of the stratigraphy and mineral compositions at Wadi Qutabah with intrusions bearing PGE deposits suggests prospective areas for mineral exploration to the north and south of the study area. Recent reviews identify many similar-aged, mafic–ultramafic intrusive complexes across the Arabian–Nubian Shield. The large size of the Suwar – Wadi Qutabah Complex, its noritic composition, and subcontinental lithospheric mantle signature are characteristics typical of mafic rocks formed in extension-related, continental rift settings. Thus, the Suwar – Wadi Qutabah Complex may be part of a previously unrecognized large igneous province associated with a late Proterozoic magmatic event and preserved in what is today, the Arabian Shield.

Platinum-group element geochemistry of mafic rocks from the Dongchuan area, southwestern China

2016 ◽  
Vol 36 (1) ◽  
pp. 52-65 ◽  
Author(s):  
Siqi Yang ◽  
Hong Zhong ◽  
Weiguang Zhu ◽  
Wenjun Hu ◽  
Zhongjie Bai
Keyword(s):  
Platinum Group Element ◽  
Group Element ◽  
Southwestern China ◽  
Element Geochemistry ◽  
Mafic Rocks ◽  
Platinum Group

Magnetite Chemistry by LA-ICP-MS Records Sulfide Fractional Crystallization in Massive Nickel-Copper-Platinum Group Element Ores from the Norilsk-Talnakh Mining District (Siberia, Russia): Implications for Trace Element Partitioning into Magnetite

2020 ◽  
Vol 115 (6) ◽  
pp. 1245-1266 ◽  
Author(s):  
Charley J. Duran ◽  
Sarah-Jane Barnes ◽  
Eduardo T. Mansur ◽  
Sarah A.S. Dare ◽  
L. Paul Bédard ◽  
...  
Keyword(s):  
Solid Solution ◽  
Fractional Crystallization ◽  
Platinum Group Element ◽  
Group Element ◽  
Sulfide Liquid ◽  
Mining District ◽  
Monosulfide Solid Solution ◽  
Sulfide Deposits ◽  
Chalcophile Elements ◽  
Platinum Group

Abstract Mineralogical and chemical zonations observed in massive sulfide ores from Ni-Cu-platinum group element (PGE) deposits are commonly ascribed to the fractional crystallization of monosulfide solid solution (MSS) and intermediate solid solution (ISS) from sulfide liquid. Recent studies of classic examples of zoned orebodies at Sudbury and Voisey’s Bay (Canada) demonstrated that the chemistry of magnetite crystallized from sulfide liquid was varying in response to sulfide fractional crystallization. Other classic examples of zoned Ni-Cu-PGE sulfide deposits occur in the Norilsk-Talnakh mining district (Russia), yet magnetite in these orebodies has received little attention. In this contribution, we document the chemistry of magnetite in samples from Norilsk-Talnakh, spanning the classic range of sulfide composition, from Cu poor (MSS) to Cu rich (ISS). Based on textural features and mineral associations, four types of magnetite with distinct chemical composition are identified: (1) MSS magnetite, (2) ISS magnetite, (3) reactional magnetite (at the sulfide-silicate interface), and (4) hydrothermal magnetite (resulting from sulfide-fluid interaction). Compositional variability in lithophile and chalcophile elements records sulfide fractional crystallization across MSS and ISS magnetites and sulfide interaction with silicate minerals (reactional magnetite) and fluids (hydrothermal magnetite). Estimated partition coefficients for magnetite in sulfide systems are unlike those in silicate systems. In sulfide systems, all lithophile elements are compatible and chalcophile elements tend to be incompatible with magnetite, but in silicate systems some lithophile elements are incompatible and chalcophile elements are compatible with magnetite. Finally, comparison with magnetite data from other Ni-Cu-PGE sulfide deposits pinpoints that the nature of parental silicate magma, degree of sulfide evolution, cocrystallizing phases, and alteration conditions influence magnetite composition.

PLATINUM GROUP ELEMENT (PGE) SYSTEMATICS OF ARC SULFIDES: A CASE STUDY FROM CUMULATES OF THE CHILAS COMPLEX, KOHISTAN ARC, PAKISTAN

2016 ◽  
Author(s):  
Ijaz Ahmad ◽  
◽  
Jeremy P. Richards ◽  
Jingao Liu ◽  
D. Graham Pearson ◽  
...  
Keyword(s):  
Platinum Group Element ◽  
Group Element ◽  
Platinum Group

scholarly journals The komatiite-mantle platinum-group element paradox

2021 ◽  
Author(s):  
Pedro Waterton ◽  
James Mungall ◽  
D. Graham Pearson
Keyword(s):  
Platinum Group Element ◽  
Group Element ◽  
Platinum Group
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